Reverse-engineering the 8086's Arithmetic/Logic Unit from die photos

131 · Ken Shirriff · Aug. 22, 2020, 4 p.m.
.hilite {cursor:zoom-in} The Intel 8086 processor was introduced in 1978, setting the course of modern computing. While the x86 processor family has supported 64-bit processing for decades, the original 8086 was a 16-bit processor. As such, it has a 16-bit arithmetic logic unit (ALU).1 The arithmetic logic unit is the heart of a processor: it performs arithmetic operations such as addition and subtraction. It also carries out Boolean logic operations such as bitwise AND and OR as well as als...